From the Greek: scale and wing
With more than 105.000 known species, the Lepidoptera is one of the four largest insect orders. It is difficult to divide the order into sound, manageable groups. Two popular approaches have had wide currency, but are quite without scientific validity. The distinction between micro- and macrolepidoptera is artificial: the latter group may be defined as including species large enough to be pinned conveniently into the collector's cabinet, the former includes all Lepidoptera too small for the average collector to bother with. The concepts of Rhopalocera and Heterocera are merely latinized expressions of the distinction between butterfly and moth respectively. It is true that butterflies probably are compact phylogenetically, but to obtain equivalent grouping of the moth families would require a whole series of categories.
Lepidoptera can be divided into four suborders: Zeugloptera, Aglossata, Heterobathmiina and Glossata (Kristensen, 1984)
Most larvae are phytophagous, feeding on leaves or sprouts. Many are quite destructive and Lepidoptera includes a large number of major agricultural pests. The pupae of the most primitive families are decticous exarate, able to move about with comparative ease; the typical and more familiar lepidopterous pupa is adecticous and almost immobile. Pupation is passed in a silken cocoon or in a silk-lined chamber beneath the ground. The silken button or button-and-girdle arrangement of butterfly pupae is a vestigial cocoon.
Adults feed little or not at all and in some families the mouthparts are atrophied. Those that do feed take various liquids, especially flower nectar. Usually the imago lives only a short time, though a few overwinter in the northern temperate zone. A general trend in Lepidoptera is to reduce the activity and importance of the adult to a brief period of reproduction, and to prolong and to increase the importance of the larval instars.
Characteristics:
Minute to very large insects with soft cylindrical bodies. Body, wings and appendages generally covered with pigmented scales providing colour patterns characteristic of species. Hypognathous, relatively small head free on slender neck. Large compound eyes well separated; 2 or no ocelli. Antennae slim, the numerous variations characteristic of major groups. Ectognathous mouthparts mandibulate in several primitive families; in all others, mouthparts with vestigial mandibles and the maxillae modified to form a sucking proboscis coiled in repose or maxillae vestigial. Thoracic segments strongly fused. Wings well developed, proportionately large, the hindwings smaller, longitudinal venation strong with few cross veins, in repose held in various positions; few apterous forms. Legs with large coxae fixed; tarsi basically 5-segmented, post-tarsi with paired claws. 10-segmented abdomen frequently partly fused or telescoped, not all segments usually evident. Cerci absent. Oviparous; holometabolous, polypod larvae generally terrestrial (a few aquatic), pupae decticous or (more often) adecticous (Fox and Fox, 1966).